This invention relates to improvements in an airconditioner utilizing a vapor compressing and refrigerating cycle, and particularly to such an airconditioner having an increased airconditioning capability during a drop in outdoor temperature to efficiently cool and warm and associated room or rooms during the whole year.
Heretofore there have been widely employed airconditioners having a vapor compressing and refrigerating cycle. Because the atmosphere is used as a heat source, these airconditioners have been characterized in that the capability of warming an associated room or rooms decreases with a reduction in outdoor temperature, for example, in the winter, in cold districts, in the morning or in the evening. Particularly they have encountered the problem that, when the outdoor air falls to a few degrees Centigrade above the water freezing temperature, frost is produced on the surface of the outdoor heat exchanger resulting in a deterioration of the heat exchange capability thereof.
There has already been proposed some approaches to that problem occurring in the room warming mode of operation utilizing the atmosphere as a heat source. One of the approaches has been to provide an indoor or an outdoor heat exchanger with an electric heater serving as an auxiliary heat source. For the indoor heat exchanger with the electric heater, an indoor air blower is used to directly take out warm air while for the outdoor heat exchanger with the electric heater, the refrigerant being used is heated by the electric heater for the purpose of transporting heat to the indoors. However the use of such an electric heater as the auxiliary heat source is disadvantageous in that the cost of operation is expensive as compared with other heat sources and it requires the provision of an electric power source.
Also it has been previously known to provide the outdoor heat exchanger with a water heater. This measure requires using a boiler resulting in a high cost of equipment and also in a large-sized apparatus which inevitably occupies a large area.
On the other hand, the frost on the outdoor heat exchanger can be removed in a short time when the room cooling mode of operation is performed. This measure, however, has been disadvantageous in that such defrosting increases the heat loss from the room and the room warming mode of operation must be temporarily suspended.
In addition, there has been proposed a method involving remedying the lack of room warming capability. According to this method, a combustion device is incorporated in the indoor exchanger to heat the associated heat exchanger with the resulting combustion gas thereby to supply warm air to the interior of the particular room or rooms for room warming purposes, and the combustion gas is externally exhausted after having heated the heat exchanger and the room or rooms is or are cooled by a separately provided room cooling device. However, the indoor combustion device is disadvantageous in that it is necessary to provide pipes for supplying combustion air and exhausting the exhaust gas, which results in many limitations on locating the installation.
It has also been suggested to provide the outdoor heat exchanger with a combustion device as a heat source for use in the room warming mode of the operation. The combustion gas from the combustion device supplies thermal energy for evaporating the particular refrigerant being used thereby preventing a reduction in the room capability upon a decrease in the outdoor temperature. When a high temperature combustion gas is used as the heat source, it is to be understood that means are required not only to efficiently use the heat for evaporating the refrigerant but also to overcome the problem that the heating efficiency is not high. This is because even though the outdoor heat exchanger is partly heated by the combustion device, the resulting heat is partly dissipated in the piping to the indoors.
Accordingly it is an object of the present invention to provide a new and improved airconditioner including a refrigeration circuit in which a liquid and a vapor phase of the refrigerant being used are distributed in well balanced state in all of the modes of operation so that the airconditioner can be highly economically operated during the whole year.